Study finds Brazil isn’t counting all deforestation in official estimates

A new study published in the journal Conservation Letters finds that, between 2008 and 2012, close to 9,000 square kilometers (about 3,475 square miles) of the Brazilian Amazon were cleared without being detected by the government’s official monitoring system.

Brazil’s Monitoring Deforestation in the Brazilian Amazon by Satellite Project (known as PRODES) has played a key role in Brazil’s recent efforts to rein in deforestation.

But when researchers with Brown University compared data from PRODES with two independent satellite measures of forest loss — from the Global Forest Change project and the Fire Information for Resource Management Systems — they found an area of deforestation roughly the size of Puerto Rico was not included in the PRODES monitoring.

Brazil drew widespread praise for drastically lowering Amazon deforestation over the past decade and half. But as forest destruction in the country is on the rise once again, new research finds that Brazil’s official estimates are missing large swaths of deforestation.

News broke last November that deforestation had jumped 16 percent in the Brazilian Amazon for the year ending on July 31, 2015, with an estimated 5,831 square kilometers (about 2,250 square miles) of rainforest, an area half the size of Los Angeles, destroyed that year.

The Brazilian government revised that figure earlier this month, however, stating that some 6,207 square kilometers (about 2,397 square miles) of Amazon rainforest were actually destroyed in the year that ended on July 31, 2015. Though this represents a six percent increase over the previous estimate and the highest annual loss in the Brazilian Amazon since 2011, it is still well below historical levels of deforestation.

Now a new study published in the journal Conservation Letters finds that, between 2008 and 2012, close to 9,000 square kilometers (about 3,475 square miles) of the Brazilian Amazon were cleared without being detected by the government’s official monitoring system.

Brazil’s Monitoring Deforestation in the Brazilian Amazon by Satellite Project (known as PRODES) has played a key role in Brazil’s recent efforts to rein in deforestation. According to PRODES, 25,000 square miles of Amazon rainforest were lost to deforestation in 2003. That dropped to an average of just 5,300 square miles between 2009 to 2013.

But when researchers with Brown University compared data from PRODES with two independent satellite measures of forest loss — from the Global Forest Change project and the Fire Information for Resource Management Systems — they found that about 9,000 square kilometers of rainforest destruction, an area roughly the size of Puerto Rico, were not included in the PRODES monitoring.

The Global Forest Change (GFC) dataset reveals more tree cover loss than did PRODES, which focuses on larger, more undisturbed tracts of forest. It is important to note a limitation of the GFC dataset in that it broadly measures canopy change, and so also lumps in the harvesting of tree plantations. GFC data source: Hansen/UMD/Google/USGS/NASA, accessed through Global Forest Watch

“PRODES has been an incredible monitoring tool and has facilitated the successful enforcement of policies,” Leah VanWey, a co-author of the study and senior deputy director at the Institute at Brown for Environment and Society, said in a statement. “But we show evidence that landowners are working around it in ways that are destroying important forests.”

“PRODES essentially masks out these regions and treats them as non-forest,” VanWey said. “We wanted to compare the PRODES maps with satellite sources that just look at canopy cover, without those exclusions. We showed that while deforestation in large plots of primary rainforests has declined, it has expanded in these areas not tracked by PRODES.”

Carlos Souza, a senior researcher with Brazilian NGO Imazon who was not involved in the study, said the Brown University researchers’ findings were welcome because they highlight the weaknesses of Brazil’s policies to control deforestation of secondary forests. At the state level, Pará state regulates deforestation in this type of forest, he noted. “However, the lack of official data creates challenges to implement this norm,” Souza told Mongabay.

Brazil uses PRODES to calculate the amount of greenhouse gases emitted by the burning of forest biomass every year. The findings of the Conservation Letters study suggest that the country’s deforestation-related greenhouse gas emissions are nearly twice as high as PRODES estimates, however.

VanWey and her co-authors say Brazil needs to update its detection and enforcement strategy to better reflect the realities on the ground. “By missing so much deforestation in PRODES measurements, Brazil is overestimating their emissions reductions,” VanWey said.

“There’s been a transformation in the way people do agriculture,” she added. “At the same time, the landscape has changed with emergence in recent decades of these secondary forests. We suggest that enforcement and monitoring regimes need to be updated for that new reality of land management.”

VanWey also noted that the study’s findings largely verified that Brazil’s efforts to curb deforestation have been successful, so it wasn’t all bad news.

“In some ways this is an optimistic story because it shows that the enforcement activities through PRODES were incredibly effective in protecting primary forest,” she said. “But these other forest areas are important as well, and they’re worth protecting.”